An integrated descaling-passivation functional polymer, a preparation method and application thereof

Abstract

The present application relates to a kind of integrated descaling-passivation function polymer and its preparation method and application, belong to industrial equipment chemical cleaning and corrosion protection technical field, it is single compound with formula (I) shown as follows: D-L-P (I), wherein, D is the descaling function chain segment with number average molecular weight of 2,000 to 50,000, selected from polyacrylic acid segment, polyepoxysuccinic acid segment or phosphonated polyacrylic acid segment;P is passivation function end group, selected from the following formula (II) or formula (III) shown as follows: -R 1 -1H-benzotriazole-1-yl (II), wherein R 1 It is C1-C6 straight chain or branched alkylene;-R 2 -Si (OR 3 ) 3 (III), wherein R 2 It is C1-C3 alkylene, R 3 It is C1-C2 alkyl.The integrated descaling-passivation function polymer and its preparation method and application, by covalent bond, descaling chain segment and passivation end group are connected as single molecule, force realizes "clears a point, protects a point" sequence effect, fundamentally eliminates competitive adsorption, reaches the advantage of molecular level synergistic effect.

Description

Technical Field

[0001] This invention relates to the field of chemical cleaning and corrosion protection technology for industrial equipment, specifically to a novel compound that integrates descaling and passivation functions into a single molecule through stable covalent bonds, its preparation method, and its application in a simultaneous cleaning and passivation process. Background Technology

[0002] In the field of industrial cleaning, passivating fresh metal surfaces after cleaning to prevent flash corrosion is a standard procedure. To simplify the operation, existing technologies commonly employ a physical compounding approach, combining the cleaning agent and the passivating agent. For example, the composition disclosed in patent CN1178867C comprises a mixture of a cleaning polymer, hexamethylenetetramine (a metal protectant), and dimethylcopper oxime (a metal passivating agent). However, this "physical compounding" approach has inherent drawbacks that cannot be overcome at the molecular level:

[0003] 1. Interfacial competitive adsorption: At the solid-liquid interface, free cleaning agent molecules and free passivating agent molecules operate independently and compete for limited surface adsorption sites. Passivating agents may non-selectively adsorb onto the remaining scale layer, resulting in wasted function; while strongly adsorbing cleaning agent molecules, after completing their function, may continue to occupy the metal surface, thus hindering the effective access and film formation of the passivating agent, leading to mutual inhibition of function.

[0004] 2. Asynchronous Processes: Cleaning and passivation are two independent physicochemical processes, and their timing and spatial location cannot be precisely controlled in a physical compound system. There is an unavoidable time and spatial difference between the removal of the scale and the effective coverage of the passivation film, which is the "corrosion risk window period".

[0005] 3. Uncontrollable membrane quality: Due to competitive adsorption and lack of molecular-level synergy, passivation films formed by physical adsorption are often uneven, discontinuous, and have weak adhesion. Their protective performance is unstable and difficult to predict, and is heavily dependent on operating conditions such as concentration and pH.

[0006] Therefore, physical compounding is merely a simple "mixing" of functions, not a "fusion." Its effect is the result of various random statistical behaviors of molecules, and cannot guarantee the necessary synergy between cleaning and passivation at every microscopic local site. The industry urgently needs a technical solution that can resolve this fundamental contradiction from the source of molecular design. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides an integrated descaling-passivation functional polymer, its preparation method, and its application. By connecting the descaling functional chain segment and the passivation functional end group into a single molecule through stable covalent bonds, the "cleaning-passivation" sequential synergistic effect at the molecular level is achieved, fundamentally solving the technical bottlenecks such as functional mutual inhibition, timing mismatch, and uneven film layer in traditional compound systems.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] An integrated descaling-passivation functional polymer, which is a single compound having the formula (I):

[0010] DLP(I)

[0011] in,

[0012] D is a descaling functional segment with a number average molecular weight of 2,000 to 50,000, selected from polyacrylic acid segments, polyepoxysuccinic acid segments or phosphonic polyacrylic acid segments.

[0013] P is a passivating functional end group, selected from the groups shown in formula (II) or formula (III):

[0014] -R¹-1H-benzotriazol-1-yl(II)

[0015] Where R¹ is a C1-C6 straight-chain or branched alkylene group;

[0016] -R²-Si(OR³)3(III)

[0017] Where R² is a C1-C3 alkylene group and R³ is a C1-C2 alkyl group;

[0018] L is a linking group that connects D and P, and it is an amide bond (-CONH-).

[0019] The end of the descaling functional segment D is covalently bonded to the passivation functional end group P via the amide bond L.

[0020] Furthermore, in formula (II), R¹ is methylene (-CH2-) or ethylene (-CH2CH2-).

[0021] Furthermore, in formula (III), P is a residue of γ-aminopropyltrimethoxysilyl group (-CH2CH2CH2-Si(OCH3)3).

[0022] This invention also provides a method for preparing an integrated descaling-passivation functional polymer, comprising the following steps:

[0023] S1. Preparation of a descaling functional prepolymer D-COOH with a carboxyl group at one end: The descaling functional segment D is synthesized by free radical polymerization, and the molecular weight and end structure are controlled by a chain transfer agent containing a carboxyl group to obtain a prepolymer with a carboxyl group at the end.

[0024] S2. Preparation of isocyanate-terminated passivation precursor P-NCO: Reaction of benzotriazole compounds or aminosilane compounds with excess diisocyanate to obtain a passivation precursor with isocyanate groups at one end.

[0025] S3. Condensation reaction: The D-COOH obtained in step S1 and the P-NCO obtained in step S2 are reacted in the presence of a catalyst, so that the carboxyl group at the end of D-COOH and the isocyanate group of P-NCO form an amide bond L, to obtain the integrated functional polymer DLP.

[0026] Furthermore, the carboxyl-containing chain transfer agent is mercaptoacetic acid.

[0027] This invention also provides an application of an integrated descaling-passivation functional polymer, specifically its application in the preparation of an integrated cleaning and passivation agent.

[0028] This invention also provides an application of an integrated descaling-passivation functional polymer. The integrated descaling-passivation functional polymer is used in the water-side cleaning and passivation of industrial equipment. The equipment is circulated online using a treatment solution containing the functional polymer. In a single step, the polymer's intramolecular sequence action mechanism is used to simultaneously remove scale and passivate the metal surface.

[0029] Compared with the prior art, the present invention provides an integrated descaling-passivation functional polymer, its preparation method and application, which has the following beneficial effects:

[0030] 1. This integrated descaling-passivation functional polymer, its preparation method, and its application connect the descaling chain segment and the passivation end group into a single molecule through covalent bonds, forcibly achieving the sequential action of "cleaning a little and protecting a little," fundamentally eliminating competitive adsorption and achieving the advantage of molecular-level synergistic effect.

[0031] 2. This integrated descaling-passivation functional polymer, its preparation method, and its application can simultaneously complete cleaning and passivation in a single step without the need for process switching, greatly improving processing efficiency and achieving both process simplification and high efficiency.

[0032] 3. The integrated descaling-passivation functional polymer, its preparation method, and its application form a passivation film that is uniform, dense, and has strong adhesion. Its corrosion resistance is superior to that of traditional physical compound systems, which can significantly improve the quality of film formation.

[0033] 4. This integrated descaling-passivation functional polymer, its preparation method, and its application have a unique structural design and innovative mechanism, and possess strong patent protection value and industrialization potential. Attached Figure Description

[0034] Figure 1 This is a process flow diagram of an integrated descaling-passivation functional polymer, its preparation method, and its application according to the present invention. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Please see Figure 1 .

[0037] Example 1: Preparation of BTA-terminated phosphonic polyacrylic acid (D-PAA-PO3H2-CONH-P-BTA) linked by amide bonds

[0038] Step S1: Synthesize a phosphonic polyacrylic acid prepolymer (D-COOH) with a carboxyl group at one end.

[0039] Raw material ratio:

[0040] Acrylic acid: 50 g;

[0041] 2-phosphono-1,2,4-tricarboxylate butane (phosphorus-containing monomer): 10 g;

[0042] Thioglycolic acid (chain transfer agent): 1.2 g;

[0043] Ammonium persulfate (initiator): 0.5 g;

[0044] Deionized water: 200 mL.

[0045] Reaction process:

[0046] Acrylic acid, a phosphorus-containing monomer, and mercaptoacetic acid were dissolved in water, and nitrogen gas was bubbled through to remove oxygen. The temperature was raised to 70°C. Ammonium persulfate aqueous solution was slowly added dropwise, and the reaction was allowed to proceed for 6 hours. After the reaction was complete, the pH was adjusted to 7-8 with sodium hydroxide solution, yielding a pale yellow transparent liquid. Small molecules were removed by dialysis, and the liquid was freeze-dried to obtain a white solid prepolymer, D-COOH. Gel permeation chromatography (GPC) determined the number-average molecular weight (Mn) to be approximately 12,000.

[0047] Step S2: Preparation of isocyanate-terminated BTA precursor (P-NCO)

[0048] Raw material ratio:

[0049] 1H-benzotriazole (BTA): 5.0 g;

[0050] Hexamethylene diisocyanate (HDI): 10.0 g (excess);

[0051] Anhydrous tetrahydrofuran: 50 mL.

[0052] Reaction process:

[0053] BTA was dissolved in tetrahydrofuran and cooled to 0-5°C in an ice bath. HDI was slowly added dropwise while stirring for 3 hours. After the reaction was complete, the solvent and unreacted HDI were removed by vacuum distillation to obtain a pale yellow oily liquid, P-NCO. Fourier transform infrared spectroscopy (FT-IR) confirmed the presence of a characteristic -NCO absorption peak at 2270 cm⁻¹.

[0054] Step S3: Condensation reaction to prepare D-PAA-PO3H2-CONH-P-BTA

[0055] Raw material ratio:

[0056] D-COOH (product of step S1): 10.0 g;

[0057] P-NCO (product of step S2): 3.5 g;

[0058] Dibutyltin dilaurate (catalyst): 0.05 g;

[0059] N,N-Dimethylformamide (DMF): 50 mL.

[0060] Reaction process:

[0061] D-COOH was dissolved in DMF, a catalyst was added, and P-NCO solution was added dropwise with stirring. The mixture was heated to 60°C and reacted for 8 hours. After the reaction was completed, the reaction solution was poured into cold diethyl ether to precipitate the product. The precipitate was filtered and dried under vacuum to obtain a pale yellow solid product. The formation of the amide bond was confirmed by ¹H NMR spectroscopy (a characteristic peak of -CONH- appeared at δ 8.2-8.5 ppm).

[0062] Example 2: Preparation of amide-linked silane-terminated polyepoxysuccinic acid-acrylic acid copolymer (D-PESA-PAA-CONH-P-Si)

[0063] Step S1: Synthesize a polyepoxysuccinic acid-acrylic acid copolymer prepolymer (D-COOH) with a carboxyl group at one end.

[0064] Raw material ratio:

[0065] Epoxysuccinic acid: 30 g;

[0066] Acrylic acid: 20 g;

[0067] Thioglycolic acid: 1.0 g;

[0068] Potassium persulfate: 0.4 g;

[0069] Water: 150 mL.

[0070] Reaction process:

[0071] Similar to Example 1, the reaction was carried out at 75°C for 5 hours under nitrogen protection, and the prepolymer D-COOH was obtained after post-treatment. GPC determination showed that Mn ≈ 8,000.

[0072] Step S2: Preparation of isocyanate-terminated aminosilane precursor (P-NCO)

[0073] Raw material ratio:

[0074] γ-aminopropyltrimethoxysilane: 5.0 g;

[0075] Isophorone diisocyanate (IPDI): 8.0 g;

[0076] Anhydrous toluene: 40 mL.

[0077] Reaction process:

[0078] Similar to Example 1, P-NCO was obtained by distillation after the reaction, and the -NCO peak was confirmed by FT-IR.

[0079] Step S3: Condensation reaction to prepare D-PESA-PAA-CONH-P-Si

[0080] Similar to Example 1, the product was catalyzed in DMF with dibutyltin dilaurate and reacted at 60°C for 6 hours. After post-treatment, the structure was confirmed by ¹H NMR and FT-IR.

[0081] Example 3: Interfacial Adsorption Kinetics and Mechanism Verification Experiment

[0082] To verify the intramolecular synergistic mechanism of the present invention, the following experiments can be conducted:

[0083] 1. Quartz Crystal Microbalance Dissipation Monitoring Experiment

[0084] Sample preparation:

[0085] Four treatment solutions were prepared: ① containing only the D-segment polymer; ② containing only free BTA; ③ physically compounded D+BTA; ④ the DLP compound of this invention.

[0086] Test conditions:

[0087] A calcium carbonate-simulated scale layer was deposited on a QCM-D gold chip, and the above solution was sequentially passed through it at a flow rate of 0.1 mL / min and a temperature of 25 °C.

[0088] Results analysis:

[0089] The physical compound system exhibits significant fluctuations in ΔF and ΔD, indicating adsorption competition. In the system of this invention, ΔF continuously decreases while ΔD increases significantly, and the mass loss rate after rinsing is <10%, proving that the adsorption is strong and there is no competitive desorption.

[0090] 2. Single-molecule force spectroscopy experiment using atomic force microscopy

[0091] Probe modification:

[0092] DLP molecules are covalently fixed to the tip of the AFM probe via silane ends.

[0093] Force-distance curve test:

[0094] Tests were conducted on the surfaces of calcium carbonate film and clean iron film, respectively.

[0095] Results analysis:

[0096] The presence of multi-stage separation force curves on the calcium carbonate surface corresponds to the multiple interactions between the D segment and the scale layer; the presence of strong adhesion characteristic peaks on the iron surface corresponds to the binding of the P end with the metal, confirming the "one molecule, two functions" mechanism.

[0097] The performance comparison data in this embodiment is shown in Table 1.

[0098] Table 1

[0099] Test Project DLP Physical compound (D+P) Prior art (CN1178867C) Mechanistic conclusions QCM-D adsorption layer strength High (quality loss rate after rinsing <10%) Medium to low (30-50% loss after rinsing) No specific testing This invention demonstrates that the adsorption is the strongest and there is no competitive desorption. AFM single-molecule specific binding <![CDATA[Shows strong adhesion to both the CaCO3 and Fe surfaces]]> Free D or P adheres only to a single surface not applicable Directly confirms "bifunctionality of one molecule" and its potential for sequence action. Simultaneous film formation (EIS) Excellent (impedance continues to increase steadily) Good (Slow or fluctuating growth) Difference Prove intramolecular synergistic formation of high-quality membranes Immediate corrosion rate after cleaning 0.008 mm / y 0.035 mm / y >0.15 mm / y The manifestation of comprehensive performance advantages

[0100] Industrial Application Examples

[0101] The DLP polymer prepared in Example 1 was formulated into a 0.5 wt% aqueous solution and used for online cleaning and passivation treatment of condenser pipes in a power plant. After 12 hours of continuous treatment at pH 6-7, temperature 40℃, and circulation flow rate 1 m / s:

[0102] Descaling rate: >95% (measured by scale reduction);

[0103] Passivation film impedance: >5×10 5 Ω·cm² (electrochemical impedance spectroscopy measurement);

[0104] Corrosion rate after shutdown: <0.01 mm / y (weight loss method).

[0105] The process eliminates the need to switch between cleaning and passivation steps, achieving true one-step simultaneous processing.

[0106] in conclusion:

[0107] This invention provides an integrated descaling and passivation functional polymer based on chemical bonding. Through innovative DLP molecular design, it achieves a qualitative leap from "physical mixing" to "chemical fusion." The unique "intramolecular sequence action mechanism" fundamentally solves the technical pain points of traditional physical compounding. Supplementary interfacial adsorption kinetic experiments (QCM-D, AFM) provide direct and compelling evidence for this innovative mechanism. This technical solution has outstanding advantages in scientific rigor, advancement, and practicality, possessing extremely high industrialization value and patent licensing prospects.

[0108] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0109] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An integrated descaling-passivation functional polymer, characterized in that, It is a single compound having the formula (I): DLP(I) in, D is a descaling functional segment with a number average molecular weight of 2,000 to 50,000, selected from polyacrylic acid segments, polyepoxysuccinic acid segments or phosphonic polyacrylic acid segments. P is a passivating functional end group, selected from the groups shown in formula (II) or formula (III): -R¹-1H-benzotriazol-1-yl(II) Where R¹ is a C1-C6 straight-chain or branched alkylene group; -R²-Si(OR³)3(III) Where R² is a C1-C3 alkylene group and R³ is a C1-C2 alkyl group; L is a linking group that connects D and P, and it is an amide bond (-CONH-). The end of the descaling functional segment D is covalently bonded to the passivation functional end group P via the amide bond L.

2. The integrated descaling-passivation functional polymer according to claim 1, characterized in that, In formula (II), R¹ is methylene (-CH2-) or ethylene (-CH2CH2-).

3. The integrated descaling-passivation functional polymer according to claim 1, characterized in that, In formula (III), P is a residue of γ-aminopropyltrimethoxysilyl group (-CH2CH2CH2-Si(OCH3)3).

4. A method for preparing the integrated descaling-passivation functional polymer as described in any one of claims 1-3, characterized in that, Includes the following steps: S1. Preparation of a descaling functional prepolymer D-COOH with a carboxyl group at one end: The descaling functional segment D is synthesized by free radical polymerization, and the molecular weight and end structure are controlled by a chain transfer agent containing a carboxyl group to obtain a prepolymer with a carboxyl group at the end. S2. Preparation of isocyanate-terminated passivation precursor P-NCO: Reaction of benzotriazole compounds or aminosilane compounds with excess diisocyanate to obtain a passivation precursor with isocyanate groups at one end. S3. Condensation reaction: The D-COOH obtained in step S1 and the P-NCO obtained in step S2 are reacted in the presence of a catalyst, so that the carboxyl group at the end of D-COOH and the isocyanate group of P-NCO form an amide bond L, to obtain the integrated functional polymer DLP.

5. The preparation method of the integrated descaling-passivation functional polymer according to claim 4, characterized in that, In step S1, the carboxyl-containing chain transfer agent is mercaptoacetic acid.

6. The application of an integrated descaling-passivation functional polymer, as described in any one of claims 1-3, in the preparation of an integrated cleaning and passivation agent.

7. An application of an integrated descaling-passivation functional polymer, as described in any one of claims 1-3, in the water-side cleaning and passivation of industrial equipment, characterized in that... The equipment is circulated online using a treatment solution containing the aforementioned functional polymer. In a single step, the intramolecular sequence action mechanism of the polymer is utilized to simultaneously remove scale and passivate metal surfaces.

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